Folding knife



FIG. 1 is a left-side elevational view of a folding knife;

FIG. 2 is a right-side elevational view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a back elevational view thereof; and,

FIG. 6 is a front elevational view thereof. 

The ornamental design for a folding knife, as shown and described. 